Balancing apparatus for a rotating body

ABSTRACT

A balancing apparatus for a rotating body mounted on a spindle comprises a support for first and second motors being rotatably disposed on the spindle, the motors being secured on the support at diametrically opposed points relative to the spindle axis, and first and second balancing weights mounted on the support and being rotatable in annular paths thereon concentric to the spindle axis. Transmission gearing is provided for permitting the first motor to drive itself and the support thereof for rotating the support about the spindle axis and for permitting the second motor to rotate the balancing weights toward and away from each other in the annular paths of travel thereof.

United States Patent Ito 1 1 BALANCING APPARATUS FOR A ROTATING BODY[72] Inventor: Teruyuki Ito, Aichi, Japan [73] Assignee: Toyoda KokiKabushiki Kaisha,

Kariya-shi, Japan [22] Filed: June 25, I971 [21] Appl. No.: 156,803

[30] Foreign Application Priority Data June 30,1970 Japan ..45/57l57[52] US. Cl ..74/573, 51/169 [51] Int. Cl. ..Fl6f 15/22 [58] Field ofSearch ..74/573; 51/169 [56] References Cited UNITED STATES PATENTS2,915,918 12/1959 Comstock et al ..74/573 51 Oct. 17,1972

3,371,450 3/1968 Board, Jr. et a1. ..51/1 69 Primary Examiner-William F.ODea Assistant Examiner-F. D. Shoemaker Attorney-Oblon, Fisher & Spivak[57] ABSTRACT A balancing apparatus for a rotating body mounted on aspindle comprises a support for first and second motors being rotatablydisposed on the spindle, the motors being secured on the support atdiametrically opposed points relative to the spindle axis, and first andsecond balancing weights mounted on the support and being rotatable inannular paths thereon concentric to the spindle axis. Transmissiongearing is provided for permitting the first motor to drive itself andthe support thereof for rotating the support about the spindle axis andfor permitting the second motor to rotate the balancing weights towardand away from each other in the annular paths of travel thereof.

6 Claims, 5 Drawing Figures P'A'TE'NTEDnm 1 1 m2 sum 1 0r 2 y In I almww i lV/V V V T%\\ \u V 5 W 3 NW m S mm a u INVENTOR TERUYUKI ITO BYZ? #43646 w? ATTORNEYS BACKGROUND OF THE INVENTION This inventionrelates generally to dynamically actuated balancing apparatus and moreparticularly pertains to a dynamically actuated balancing apparatus fora rotating body, such as a grinding wheel, selectively operable whilethe rotating body to be balanced in being rotated about a predeterminedaxis.

Heretofore, balancing apparatus have been provided for rotating bodieswherein two or move balancing weights positioned thereon are adjustedeither automatically or manually so that a resultant force of thebalancing weights is equal in magnitude to the resultant unbalancingforce. In such balancing apparatus, it is necessary to provide aclamping device for holding the balancing weights in adjusted relationand which is selectively actuable by external means. Such arrangementsconnecting the external means to the rotating clamping device constitutecomplex structural configurations and are effective to weaken thestiffness of the spindle.

In further prior art treatment of this problem, a

balancing apparatus is known wherein rotating bodies are provided withtwo stepping motors which serve as balancing weights and also areoperative to rotate themselves in the same or in counter directionsabout a spindle axis upon energization thereof. After completion of abalancing adjustment, the stepping motors are maintained energized so asto be held in the proper angularly adjusted position. The balancingweights preferably should be within the same general weight rangerelative to an imbalance to be corrected in order to easily andaccurately compensate for the imbalance. However, because the motorsbeing used as balancing weights are generally larger in weight incomparison with the imbalance in these cases, an allowable range for theangular adjustment thereof is very restricted. Accordingly, it isdifficult to easily find a balanced position wherein the resultant forceof these motors is equal in magnitude to the resultant unbalancing forcepresent, such as, for example, in grinding wheels.

SUMMARY OF THE INVENTION It is therefore an object of the presentinvention to provide an improved dynamically actuated balancingapparatus for balancing a rotating body.

Another object of the present invention is the provision of an improvedbalancing apparatus for balancing a rotating body having a pair ofbalancing weights which are in substantially the same weight range asthe imbalance to be corrected and are automatically angularly adjustableabout the axis of rotation in both phase and magnitude.

Still another object of this invention is to provide an improvedbalancing apparatus for rotating bodies of the type characterized bymotor-driven balancing weights angularly adjustable in both phase andmagnitude, wherein the balancing weights are in the same weight range asthe possible imbalance of the rotating body.

The foregoing and other objects are attained in accordance with thisinvention by rotatably mounting a support for a pair of diametricallyopposed motors mounted thereon for rotation about the axis of therotating body, such as, for example, the spindle axis of a grindingwheel, the imbalance of which is to be corrected, mounting a pair ofbalancing weights being in the same general weight range as usualimbalances of such wheels on the motor support for rotation in annularpaths thereon, and providing transmission arrangements for connectingone of the motors with the mounting means of the grinding wheel spindlefor permitting the motor to drive the motor support and the balancingweights thereon about the spindle axis and for connecting the other ofthe motors with the balancing weights for driving the weights toward andaway from each other along the prescribed annular paths of rotationthereof. Thus, an angular adjustment of the balancing weights isobtained respectively in phase as well as magnitude. In addition, themotors herein serve as clamping means for the balancing weights becausethey remain in the adjusted positions upon de-energization of themotors, even if a centrifugal force is applied on the weights.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and attendantadvantages of the present invention will be more fully appreciated asthe same becomes better understood from the following detaileddescription when considered in connection with the accompanyingdrawings, in which like reference numerals designate like orcorresponding parts throughout the several views, and wherein:

FIG. 1 is a cross-sectional view of a balancing apparatus according tothis invention;

FIG. 2 is a cross-sectional view of the balancing means taken on theline II--II of FIG. 1;

FIG. 3 is a cross-sectional view taken on the line III- III of FIG. 1;

FIG. 4 is a cross-sectional view taken on the line IV-IV of FIG. 3; and

FIG. 5 is a plan view of a wheel head provided with the balancingapparatus according to the present invention and schematicallyillustrating a control thereof.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to thedrawings, and more particularly to FIG. 5, a wheel head 10 is mounted ona base, not shown, and supports thereon a drive motor provided with adrive sheave 91 interconnected with a spindle sheave 92 through aplurality of drive belts 93.

An elongated wheel spindle 12 projecting at both ends from the wheelhead 10 supports the spindle sheave 92 at one end thereof and a wheelsleeve assembly 95 on the other end. The wheel sleeve assembly 95carries a grinding wheel 16 and a dynamically actuated balancingapparatus 96 described in further detail hereinbelow.

Referring now to FIG. 1, the wheel spindle 12 is rotatably mounted inthe wheel head 10 by bearing sleeves 11 secured therein. The spindle isprovided at its left end, as seen in FIG. 1, with a wheel sleeve 13secured thereto by a retaining nut 14. The wheel sleeve 13 iscooperatively associated with a flange member 15 to clamp the grindingwheel 16 therebetween by means of bolts and the grinding wheel thussecured is thereby driven by the drive motor 90.

The wheel sleeve 13 is provided with an axially extending annularreduced portion on the outer periphery of which is mounted a rotatablesupport member 21, such as on needle roller bearings. An integral flange22 formed on the rotatable support member 21 extends radially therefromat the right end thereof and a circular flange plate 23 is boltedthereto at the left end. A worm wheel 24 is fixed on the left end faceof the annular portion 20 in concentric relation with the wheel spindle12 being in contact with the left end of the circular plate 23 foraxially retaining the circular plate 23 and the support member 21.

A pair of ring gears 25 and 26 are rotatably mounted on the outerperiphery of the support member 21 in axially spaced relation so as totravel in respectively spaced annular paths. Secured to the ring gears25 and 26 are a pair of segmentally formed balancing weights 27 and 28each having the same weights.

For adjusting the balancing weights, a pair of motors 30 and arerespectively mounted on support blocks 31 and 41 secured on the left endsurface of the circular plate 23. The motors 30 and 40 are arranged atdiametrically opposed positions relative to the axis of the spindle 12and are arranged in such a manner that the drive shafts thereof aredisposed in tangential relation to the wheel spindle 12.

Motor 30 is provided with a pinion 32 keyed to the drive shaft thereof.The pinion 32 engages another pinion 34 mounted on a worm shaft 33 whichis rotatably supported by suitable bearings in the support block 31, notshown, the worm shaft 33 being provided with a worm 35 engaging the wormwheel 24 secured to the wheel sleeve 13.

When the motor 30 is energized, it will rotate in predetermineddirections and drive itself around the worm wheel 24 and thus around therotary axis of the wheel spindle 12 through the pinions 32,34 and worm35. Therefore, with the rotation of the motor 30, the support block 31,the circular plate 23 and all other parts mounted thereon are alsorotated. The transmission means includes a worm gearing consisting ofthe worm 35 and the worm wheel 24, and accordingly is nonreversible andis operable only when the motor 30 is energized.

In the support block 41, a worm shaft 43 provided with a worm 45 issecured by a set-screw to a drive shaft 42 of the second motor 40, asshown in FIG. 2, and is rotatably supported by a bearing 44 arrangedtherein. A worm wheel 46 meshing with the worm 45 is keyed at one end ofa worm wheel shaft 48 rotatably supported in parallel relation with thespindle axis by a bearing 47 in the support block 41 and extendingthrough the circular plate 23. The worm wheel shaft 48 is provided witha pinion 49 at the other end thereof which engages a pinion 51 mountedon one end of a pinion shaft rotatably supported by both the circularplate 23 and the flange 22. Another pinion 52 at the other end of thepinion shaft 50 engages with the second ring gear 26 carrying the secondbalancing weight 28.

Another pinion shaft 53 is rotatably supported in parallel relation withthe pinion shaft 50 also being carried by both the circular plate 23 theflange 22 as shown in FIG. 4, and has a long pinion 54 which engagesboth the pinion 51 and the ring gear 25 having the balancing weight 27thereon.

Therefore, when the second motor 40 is energized, it rotates inpredetermined directions and drives the worm 45, the worm wheel 46,pinions 49,51,52 52 and 54. Accordingly, the balancing weights 27 and 28are rotatable towards and away from each other on the outer periphery ofthe support member 21. This second transmission means includes a wormgearing consisting of the worm 45 and the worm wheel 46. Asin the othertransmission, it is nonreversible and is operable only when the secondmotor 40 is energized.

All parts on the circular plate 23 including the motors 30 and 40, thesupport blocks 31 and 41 and the transmissions are balanced relative tothe spindle axis.

The wheel spindle 12 is further provided with a central through bore 60,as shown best in FIG. 3, to receive a tube 61 rotatably mounted in thewheel spindle 12 at opposite ends thereof by bearing sleeves 64 and 97.At the left end of the tube 61, FIG. 1, there is provided a bushing 62fixed thereto by a nut 63. The bushing 62 is covered by a cap 65 made ofa suitable insulating material and being provided with a plurality ofconnectors 66. As shown in FIG. 5, the tube supports at the right endthereof a slip-ring assembly 94, in a manner well known to those skilledin the art. The connectors 66 support leads serving to connect themotors 30 and 40 with a power source, not shown, through the tube 61 andthe slip-ring assembly 94.

As shown in FIG. 2, a drive plate 70 is secured to the circular plate 23by bolts and is provided with keys 71 projecting from the inner partthereof. In turn, the cap 65 is held against rotation relative to thedrive plate 70 by engagement of keyways 72 with keys 7]. Thereby, whenthe first motor 30 is energized, the tube 61 and the cap 65 are rotatedtherewith and the relative arrangement between the various connectors 66on the cap and the first motor is maintained constant.

An operating control system for motors 30 and 40 is schematicallyillustrated in FIG. 5. A vibration transducer mounted on the wheel head10 serves to detect any vibrations set up by an unbalance of therotating bodies and to convert such into electric signals. An amplifier81 amplifies the output of the transducer 80 and supplies a directcurrent voltage of a magnitude proportional to the degree of unbalanceto an indicating device 82 to indicate the unbalance on a meter 83. Acontrol panel 84 is connected with the slip-ring assembly 94 through anelectric circuit 98 including an electric power source and is providedwith push buttons 85,86,87 and 88. The push buttons 85 and 86 serve toenergize the motor 30 for rotating it, respectively, clockwise andcounterclockwise about the wheel spindle axis. The push buttons 87 and88 serve to rotate the other motor 40, respectively, clockwise andcounterclockwise to rotate the balancing weights 27 and 28,respectively, toward and away from each other, as best illustrated inFIG. 3.

In operation, when the wheel drive motor 90 is energized, the wheelspindle 12 holding the grinding wheel 16 is rotated. As a result, avibration is generated ac cording to the degree of unbalance of therotating bodies including the grinding wheel 16. The magnitude or theamplitude of the vibration is detected in the vibration transducer 80and is indicated in the indicating device 82 through the amplifier 81.

At first, an operator will continue to depress the push button 85 tocause the first motor 30 to rotate around the spindle axis. That is, thefirst motor 30 drives itself clockwise, as viewed in FIG. 2, about theworm wheel 24 and about the axis of the wheel spindle 12 so as torevolve the system, including the balancing weights 27 and 28 supportedon the circular plate 23 and the movable support 21. If the operatornotes that the amplitude of the vibration is increasing, he ceasesimmediately from depressing the push button 85 and instead depresses theother push button 86 to reverse the rotation of the first motor until aminimum vibration level or amplitude is noted.

In the next step, he will continue to depress the push button 87 or 88to rotate the second motor about its axis. According to this rotation,the balancing weights are rotated towards or away from each other by thesame angle of displacement. If the amplitude of the vibration isincreasing, the one push button 87 or 88 is released and the other isdepressed to reverse the travelling direction of the balancing weightsuntil a minimum vibration level less than the first such level providedin the first step is noted.

As previously mentioned, the present balancing I device includes thefirst motor 30 for changing in phase the balancing weights so that theresultant unbalancing force acts along a line bisecting the anglebetween the balancing weights, and further includes the second motor 40for changing the angle between the balancing weights in equal incrementsfrom the acting line of the unbalancing force so that the resultantforce of the balancing weights is equal in magnitude to the resultantunbalancing force.

Obviously, many modifications and variations of the present inventionare possible in light of the teachings of this invention. It is to beunderstood, therefore, that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically set forthherein.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. ln a device having means for rotatably mounting a body on a spindle,a balancing apparatus for the rotating body comprising:

support means rotatably disposed on said body mounting means forrotation about the axis of said spindle;

first and second motors mounted on said support means at diametricallyopposed positions relative to the spindle axis;

first and second balancing weights mounted on said support means andbeing rotatable thereon in annular paths concentric to said spindleaxis;

first transmission means connecting said first motor with said bodymounting means for permitting said first motor to rotate said supportmeans thereof about said body mounting means; and

second transmission means connecting said second motor with said firstand second balancing weights for permitting said second motor to movesaid first and second balancing weights toward and away from each otheralong said annular paths.

2. A balancing apparatus according to claim 1, further comprising meansfor connecting said motors through said spindle to a power source.

3. A balancing apparatus according to claim 2, wherein said means forconnecting said motors to a ower source com rises: p a tabular memb rextending through said spindle m rotatable relation therewith and beingrestrained against rotation relative to said support means at one endthereof; and

a slip-ring assembly mounted on the other end of said tube connectedthrough said tube with said motors.

4. A balancing apparatus according to claim 1,

wherein:

said first transmission means includes a first worm wheel secured onsaid mounting means and a first worm meshingly engaging said first wormwheel and being connected with said first motor; and

said second transmission means includes a second worm connected withsaid second motor and a second worm wheel meshingly engaging said secondworm and being operably connected with said first and second balancingweights.

5. A balancing apparatus according to claim 4,

wherein said second worm wheel is connected with one of said balancingweights through a drive pinion connected with said second worm wheel anda driven pinion meshing therewith, and is connected with the other ofsaid balancing weights through a third pinion engaging said drivenpinion.

6. A balancing apparatus according to claim 4,

wherein each of said first and second balancing weights includes a ringgear and a segment weight thereon, said segment weights being axiallyspaced from each other on said spindle axis.

1. In a device having means for rotatably mounting a body on a spindle,a balancing apparatus for the rotating body comprising: support meansrotatably disposed on said body mounting means for rotation about theaxis of said spindle; first and second motors mounted on said supportmeans at diametrically opposed positions relative to the spindle axis;first and second balancing weights mounted on said support means andbeing rotatable thereon in annular paths concentric to said spindleaxis; first transmission means connecting said first motor with saidbody mounting means for permitting said first motor to rotate saidsupport means thereof about said body mounting means; and secondtransmission means connecting said second motor with said first andsecond balancing weights for permitting said second motor to move saidfirst and second balancing weights toward and away from each other alongsaid annular paths.
 2. A balancing apparatus according to claim 1,further comprising means for connecting said motors through said spindleto a power source.
 3. A balancing apparatus according to claim 2,wherein said means for connecting said motors to a power sourcecomprises: a tabular member extending through said spindle in rotatablerelation therewith and being restrained against rotation relative tosaid support means at one end thereof; and a slip-ring assembly mountedon the other end of said tube connected through said tube with saidmotors.
 4. A balancing apparatus according to claim 1, wherein: saidfirst transmission means includes a first worm wheel secured on saidmounting means and a first worm meshingly engaging said first worm wheeland being connected with said first motor; and said second transmissionmeans includes a second worm connected with said second motor and asecond worm wheel meshingly engaging said second worm and being operablyconnected with said first and second balancing weights.
 5. A balancingapparatus according to claim 4, wherein said second worm wheel isconnected with one of said balancing weights through a drive pinionconnected with said second worm wheel and a driven pinion meshingtherewith, and is connected with the other of said balancing weightsthrough a third pinion engaging said driven pinion.
 6. A balancingapparatus according to claim 4, wherein each of said first and secondbalancing weights includes a ring gear and a segment weight thereon,said segment weights being axially spaced from each other on saidspindle axis.